B6100 with B670 BACKHOE how to figure out weak link

[X32]

My B670 backhoe is real strong and easily lifts up tractor in the air as you can see from the picture but the power/force of the backhoe to bend the arm in or towards the tractor seems weak. In other words there is a lot of force when I extend the arm down but not a lot of force when I try to curl the arm in. So I realize that I have a problem but not sure how to figure out where the problem is any suggestions would be appreciated.

 

[North Idaho Wolfman]

Blown or leaking seal on the cylinder is the most likely the cause of the weakness.
If possible you could swap the lines from one side to the other and if still week in the same direction then it's the cylinder, but if it move to the other direction it's the valve (not very common).

 

[X32]

Blown or leaking seal on the cylinder is the most likely the cause of the weakness.
If possible you could swap the lines from one side to the other and if still week in the same direction then it's the cylinder, but if it move to the other direction it's the valve (not very common).

interesting please excuse my ignorance but just to be clear when you say cylinder your speaking of the hydraulic cylinder that extends and contracts correct? And taking the lines switching them which in turn will make the controls work opposite correct?

 

[North Idaho Wolfman]

interesting please excuse my ignorance but just to be clear when you say cylinder your speaking of the hydraulic cylinder that extends and contracts correct? And taking the lines switching them which in turn will make the controls work opposite correct?

Yes and yes
You would switch them back after the test.

 

[mendonsy]

A quick way to test for an internal cylinder leak would be to raise the dipper arm to a horizontal position and watch to see how fast it leaks down. If the cylinder has an internal leak it will drop down fairly quickly

 

[X32]

A quick way to test for an internal cylinder leak would be to raise the dipper arm to a horizontal position and watch to see how fast it leaks down. If the cylinder has an internal leak it will drop down fairly quickly

that's kind of what I figured but the strange thing is that I only have one hydraulic cylinder that is leaking down but it's also very strong my weakest hydraulic cylinder does not leak down, go figure LOL

On another note wears a good place to buy hydraulic cylinder rebuild kits? I just price that Kubota and it's 57 bucks

 

[Lil Foot]

When I rebuilt mine, (2011) I ordered from Keller Bros, 15.70 per kit, & shipping, part #70050-00123. But I'm told any competent hydraulic shop should have all the parts necessary, because the cylinders are standard 2". (not metric)

WHOA! Hold the presses! After studying my receipts further, I find I have two sets of receipts, one for part #70050-00123, and another for part #70020-00851, both marked for boom, dip, & curl. I remember one of them was wrong, & I sent them back in exchange for the correct ones. Only problem is that I can't remember which was which, and the receipts aren't clear either. Maybe I shoulda kept my mouth shut.

 

[mendonsy]

Does the B670 have individual pressure relief for each cylinder??? Could be that the pressure on that cylinder is set lower??

 

[DaveB6200]

When I rebuilt mine, (2011) I ordered from Keller Bros, 15.70 per kit, & shipping, part #70050-00123. But I'm told any competent hydraulic shop should have all the parts necessary, because the cylinders are standard 2". (not metric)

WHOA! Hold the presses! After studying my receipts further, I find I have two sets of receipts, one for part #70050-00123, and another for part #70020-00851, both marked for boom, dip, & curl. I remember one of them was wrong, & I sent them back in exchange for the correct ones. Only problem is that I can't remember which was which, and the receipts aren't clear either. Maybe I shoulda kept my mouth shut.

If the receipts have dates on them then the last on purchased would be the right one......no?

 

[X32]

Does the B670 have individual pressure relief for each cylinder??? Could be that the pressure on that cylinder is set lower??

don't believe that there is a individual pressure relief valve for each cylinder at this point playing with it some more I am pretty sure I need to rebuild my one cylinder because all of the other cylinders make a similar noise when they are being highly stressed (Pushed to its limit) except for the weak one, my hypothesis is that because the cylinder seal is faulty the oil simply passes by that circuit and the pressure relief valve doesn't get triggered which makes a high-pitched sound(I think that makes sense) so I'm looking forward to the rebuild ordered kit today from Kabota $54 Plus ordered the wrench to remove the endcap. I am really looking forward to seeing how this performs once complete. I figured I would play it safe and go for 54 bucks and if all goes well and I decide to rebuild all the cylinders I will go the $17 route recommended.

Thank you kindly for all the help what a wonderful resource!!!

 

[Lil Foot]

If the receipts have dates on them then the last on purchased would be the right one......no?

If they were dated, yes. Damn.

 

[MagKarl]

Some of it is possibly technique related. Curling the bucket rather than crowd with the dipper stick will help.